The overall goal of this project is to develop, formally benchmark and validate a new flow sensor that will accurately quantify varying degrees of ventilation in pediatric and adult patient populations. The flow sensor is a simple, non-contact, disposable part that provides quantitative measurement of respiratory activity, even in the low-flow range. Current technologies lack the ability to accurately measure tidal volume but rather provide a semi-quantitative measure of respiratory patterns. A pneumotachograph (which can provide quantitative data) is too burdensome on patient comfort and breathing effort to obtain long term respiration measurements. Self-funded preliminary prototypes were developed prior to this grant submission and tested at the Johns Hopkins Sleep Disorders Center in Baltimore. The prototypes performed comparable to the gold standard (pneumotachograph). This project will finish development of the design, formally benchmark the flow sensor with the pneumotachograph, as well as examine the stability and accuracy of the design. Following this, the design will undergo planned improvements related to patient comfort and compliance. The project will conclude with formal clinical validation studies at overnight sleep clinics across a spectrum of patients to compare and validate the new flow sensor to current technology. Final design modifications will focus on optimization of a "plug-and-play" interface thereby simplifying integration with existing polysomnographic recording units and improving technician ease of use and patient comfort. The data and prototypes generated by this application will ultimately translate into improved care of patients that are susceptible to ventilatory failure and eventually as an ambulatory diagnostic system for patients in the home setting. This flow sensor will have an immediate impact on patient monitoring in sleep laboratories and will further influence diagnostic procedures in pulmonary medicine, anesthesia and other medical disciplines.